STUDIES ON METATHETICAL AND THERMAL POLYMERIZATION OF 5-NORBORNENE 2,3-DICARBOXIMIDE END-CAPPED RESINS .2.

The article deals with synthesis, characterization, and polymerization of 5-norbornene-2,3-dicarboximide end-capped resins (bisnadimides) ba sed on 4,4'-diaminodiphenylether, 1,4/1,3-bis(4'-aminophenoxy) benzene , 2,2'-bis[4-(4'-aminophenoxy) phenyl] propane, and bis[4-(4'-aminophe noxy)phenyl] sulphone. Both exo and endo bisnadimides were prepared by reacting the aromatic diamines with exo or endo nadic anhydride in gl acial acetic acid at 120 degrees C. The exo or endo bisnadimides could be distinguished on the basis of differences observed in IR or H-1-NM R spectra. Both thermal (in solid state) and metathetical polymerizati on (using WCl6/tetramethyltin catalyst and chlorobenzene solvent) of b isnadimides was carried out. Only exo bisnadimides could be polymerize d using metathesis reaction whereas thermal polymerization of both end o and exo bisnadimide could be successfully carried out at 300 degrees C in static air atmosphere. The polymers were highly crosslinked and insoluble in common organic solvents. The polymers obtained by metathe sis polymerization were light brown in color whereas those obtained by thermal polymerization were dark brown in color. Thermal stability of the thermally polymerized exo or endo bisnadimides was comparable. Th ese polymers were stable up to 400 degrees C and decomposed in a singl e step above this temperature. The char yield at 800 degrees C depende d on the structure of the polymer and was in the 39-56% range. The pol ymers formed by metathesis polymerization showed a 1-3% weight loss in the temperature range 226-371 degrees C and decomposed in a single st ep above 440 degrees C. The char yields were higher in these polymers (53-71%) compared to those obtained by thermal polymerization. (C) 199 7 John Wiley & Sons, Inc.